Randomisation and recruitment process
The randomisation sequence was generated using a table of
random numbers. Random permuted blocks of size four
were used to ensure a balanced design. The blocks are the
possible permutations of a sequence of four allocations – two
women each belonging to the experimental and control
groups. There are six possible arrangements of this sequence
(ABAB, ABBA, BABA, BBAA, BAAB, AABB) – where A
and B represent the groups. On the table, numbers 1–6 were
assigned to each arrangement and those outside this range
were excluded. Based on the sequence of treatments
generated using this method, treatment groups (A and B)
were written on pieces of cardboard paper and put into
sealed opaque envelopes. Each of the opaque envelopes had
a serial number on it.